1. Field of the Invention
This invention relates to the field of speech synthesizers and more specifically to speech synthesizers responsive to an input code from a code reading device.
2. Background of the Invention
Electronic speech synthesizers implemented in the form of a large scale integrated circuit (IC) are well known and commonly available. Such IC speech synthesis devices have recently become economically affordable in small volume applications. In addition, bar code and optical code reading technology have advanced to the point where inexpensive code readers are available which may be used in a multitude of portable battery powered applications.
In the entertainment and educational area, Texas Instruments Incorporated has secured patent protection for a variety of speed synthesis related devices including code readers. Examples of such devices are shown in the following U.S. Patents: U.S. Pat. No. 4,337,375 to Freeman; U.S. Pat. No. 4,189,779 to Brautingham; U.S. Pat. No. 4,466,801 to Dittakavi et al; U.S. Pat. No. 4,549,867 to Dittakavi; U.S. Pat. No. 4,505,682 to Thompson and U.S. Pat. No. 4,457,719 to Dittakavi et al.
A primary shortcoming of the devices disclosed in the above patents is the lack of flexibility and adaptability to the needs of the educational community with regard to implementing a speech synthesis device as a teaching aid. Freeman '375 suggests a speech synthesis device wherein a bar code or optical code representation supplies a code for identifying words or phrases by specifying the starting address in the vocabulary memory of the speech synthesis device of corresponding speech synthesis data. Such an addressing scheme reduces the amount of bar code information necessary for reproducing a relatively lengthy audible phase. However, given the limited density of today's electronic memories, such as system does not adequately address the difficulties in providing high quality speed reproduction by way of electronic speech synthesis, coupled with a variety of educational lesson planes. Additionally, a device which includes easily changeable memory components or electronic hardware facilitating reprogramming of memory devices in a speech synthesis device is not shown by the prior art. Thus, a hand-held portable speech synthesis device capable of reading bar codes to activate speech synthesis and having easily changeable memories or reprogrammable memories for use with educational lesson plans is needed.